MOUNTING AS-VIBRATION ISOLATOR 9W9920 - Caterpillar

The engines may be equipped with various optional engine features and controls. This section discusses general information about engine monitoring and control devices and how they operate.Marine engines can be equipped with either alarm or shutoff systems. However, in many operations an uncontrolled shutdown may cause an accident far more serious than the damage to the engine, particularly on propulsion engines.Marine propulsion engines are usually equipped with various alarm systems. The most common alarm systems indicate high jacket water temperature, low oil pressure and overspeed.Alarm systems are either electrically or mechanically operated. The operation of all electric alarms utilize components which actuate switches in a sensing unit. They are set at a less critical operating temperatures, pressures, levels or speed than shutoff controls to protect the engine from damage. The purpose of the alarm switch is to warn the operator that an unsafe operating condition is about to occur, and that corrective measures should be taken to avoid possible damage to the engine.When an alarm is activated, corrective measures should be taken before the situation becomes an emergency, or, if equipped, a corresponding shutoff device will automatically stop the engine. Manually or mechanically operated systems require resetting by pushing the RESET button until it latches. After the engine is started, oil pressure will activate the RESET button to the extended running position.When any of these components trip the alarm, the problem causing the alarm must be corrected. Familiarize yourself with the types and locations of the alarm controls, the conditions which cause the control to function, and the resetting procedure required. Caterpillar does not normally provide the alarm indicating lamp, bell or horn as part of the engine package for annunciation.Alarm switches should be electrically connected to an indicator lamp and bell or horn. The alarm should continue until the condition is corrected, then the lamp should turn OFF and silence the bell or horn.To silence the bell or horn while repairs are being made, a two-way switch and a red indicator lamp may be installed. The red indicator lamp should turn ON when the alarm is turned OFF.
The red lamp should stay ON to indicate that the engine is not protected if the switch is left in the OFF position after the repairs have been made.
Alarm Testing
During testing, abnormal operating conditions must be simulated. Perform the tests correctly to prevent possible damage to the engine.
All alarms on the engine should be tested twice a year for proper operation by referring to the Service Manual and/or contacting your authorized Caterpillar dealer.The controls should be tested every 1000 hours by authorized Caterpillar dealer personnel. Every 500 hours, the Hydramechanical Shutoff (HMSO, early engines) can be tested remotely by engine personnel.Determining Cause of Shutdown or Alarm
There are different conditions that may cause the alarm systems, usually found on an engine, to be activated. Causes for the alarm to function should be followed by performing corrective measures. Additional measures may be required by the operator, depending upon circumstances and conditions present.